Thousands of immigrants missing, presumed illegal

The agency has no idea how to find out how many of the 159,000 cases were still in Britain illegallyRui Vieira/PA

Border Agency officials have no idea whether almost 160,000 migrants have left Britain after being refused permission to extend their stay, according to a watchdog report published today.

In about 40 per cent of cases, individuals had not even been sent a notice telling them that they had 28 days to leave the country.

The latest backlog fiasco to hit the UK Border Agency was uncovered when inspectors found the cases in a “migration refusal pool” during an inspection of a local immigration team. Numbers in the pool rose by 6,000 between October and December last year to 159,313 despite guidance from officials that it should remain stable.